Russian version of the map editor for Heroes 5: "Tribes of the East" (3.1).

Does installing a new patch delete completed missions and saves?

It does not affect completed missions; saves will work incorrectly.

What exactly are you interested in? Ask questions in this thread. First, read it; there are answers to many questions. I or someone else will answer other questions. Tip: start by creating a new map ;). You should start with that :).